202 THE ZOOLOGIST. 



In extent of wings the Serotine measures about 12J- in.* 

 against 13J to 14 in. in the Noctule, so that when flying it looks 

 comparatively shorter and broader. When examined at close 

 quarters the extremity of the wing is seen to be very pointed. 

 The tail also is long and pointed. In the size of the head there 

 is apparently little difference, but the tragus is longer and 

 more pointed in the Serotine than in the Noctule. 



The dentition in the Noctule is — 



I. -I ; c. | ; pm. t ; m. f = Jf • 



In the Serotine we find — 



I. |; c. f; pm. f; m. f = ft. 



The only difference being that there are two premolars less in 

 the upper jaw of the Serotine than are found in the Noctule, and 

 the teeth (32) are fewer in number than in any other British 

 species of this family. The upper incisors are remarkably long 

 and bifid at their extremities ; the lower incisors trifid. 



The colour of the fur, which is soft, long, and silky, resembles 

 that of the Noctule in being of a deep chesnut-brown ; but there 

 is this difference observable, that whereas in the Noctule the 

 colour of the dorsal and ventral surfaces is alike, in the Serotine 

 the under parts are always much paler, approaching to grey or 

 yellowish grey. It has been remarked, however, by Bell, that 

 the Serotine is liable to greater variation in colour than any 

 other European bat. 



The general similarity of the two species here compared may 

 excuse their being sometimes confounded, especially when so 

 good a naturalist as Geoffroy made the curious mistake of 

 describing each under the name of the other ('Annales du 

 Museum,' vol. viii. p. 194). The late Dr. Gray, of the British 

 Museum, in a ' List of the Vespertilionidce of Great Britain' (Zool. 

 Journ. ii. p. 108), included the Serotine as seen " about London," 

 but we imagine the Noctule must have been mistaken for it. We 

 have observed the latter repeatedly in London flying over the 

 Serpentine, in Kensington Gardens, and around the ornamental 



* This is Bell's measurement of the extent of wings in the Serotine, but 

 we have measured specimens which extended an inch longer than this, and 

 equalled the Noctule. Some allowance must doubtless be made for the age 

 of the specimen measured. 



